Vibrator current-converting system



June 16, 1942. w, w, GARgTANG 2,286,846

VIBRATOR CURRENT-CONVERTING SYSTEM Filed July 1'7, 1940 INVENTOR.

A TTORNEYJ.

Patented June 16, 1942 VIBRATOR CURRENT-CONVERTING SYSTEM William W. Garstang, Indianapolis, Ind., assignor to Electronic Laboratories, Incorporated, Indianapolis, Ind., a corporation of Indiana Application July 17,1940, SeriaI No. 345,996

6 Claims.

The present invention relates to a vibrator system for converting direct current into alternating current.

In systems of this character and particularly in those systems which have heretofore commercially been used, wherein a vibrator switch including a resiliently mounted movable contact adapted to break and make engagement with fixed contacts on either side thereof and wherein at least one capacitor has been used and adapted to be charged periodically through the vibrating switch from the direct current source or battery and wherein an output transformer is provided, the secondary being connected to the load and primary of which is adapted to be energized periodically through the vibratory switch from the capacitor, certain objections have been found. Among these objections is, one, the comparatively low output of the system; and, two, due to the fact that there are times when, if for any reason the vibrator reed should become stuck on its initial movement, the system as a whole will become inoperative.

It is one of the objects of my present invention to provide a system having the above-men tioned characteristics without the above-mentioned objections.

By my present invention, I am able to provide a system wherein, through the, control of the vibrator, the secondary of the transformer will be charged through the discharge of the capacitor more effectively to thereby increase the output and, at the same time, the danger of inoperativeness as a result of the reed sticking on its initial movement, is prevented.

For the purpose of disclosing my invention, I have illustrated certain embodiments thereof in the accompanying drawing, in which:

Fig. 1 is a diagrammatic view of a current-converting system, including a capacitor for energizing the output circuit winding embodying my invention;

Fig. 2 is a diagrammatic view of a modification of the system illustrated in Fig. 1; and

Fig. 3 is a diagrammatic view of a still further embodiment of my invention wherein the load is disclosed as being in the nature; of a clock motor or equivalent structure.

Referring to Fig. 1, the vibrating or vibratory switch I comprises a vibratory element including a pair of resilient reeds 2 and 3, each having respectively thereon contacts 4 and 5., The contacts 4 have arranged on opposite sides thereof stationary contacts 8 and I: and the contacts 5 likewise have on opposite sides thereof stationary contacts 8 and 9. The reeds 2 and 3 are preferably connected together by a suitable armature member ID secured at their outer ends but insulated from the reeds and subject to the influence of an actuating winding ii. The stationary contacts I and 8 are connected to one terminal of a capacitor i2 which should be of the alternating current type, i. e., it should be of a non-polarized type. The opposite terminal of the capacitor [2 is connected to the primary winding I3 of an output transformer 14, the secondary l5 of which is connected to the load. The opposite terminal of the primary i3 is connected respectively to the stationary contacts 6 and 9 of the vibrator switch. In addition to the above-mentioned contacts on the vibrator switch, the reed member 2 of the switch is provided with a contact i6 normallyin engagement with a stationary contact l1. one terminal of a source of direct current in the present instance comprising the battery It. The stationary contact is connected with one terminal of the winding H and the opposite terminal of this winding is connected to the opposite terminal of the battery Ill. The reed 2 is connected to one terminal of the battery l8, and reed 3 is connected to the opposite terminal of the battery Hi.

In operation, with the contacts l6 and I1 normally closed, the winding II will be energized from the battery it through these contacts, thereby moving the vibrator reeds 3 and 2, as a unit, in a direction to open contacts l6 and I1 and in a direction to engage contacts 4 and 5 on the reeds 2 and 3 with the contacts 1 and 9. The closing of contacts 4 and I and 5 and 9 immediately establishes a circuit through the capacitor I! from one side of the battery to the opposite side of the battery, whereby a charging current flows into the capacitor i2. At the same time that contacts 4 and I and 5 and 9 are closed, contacts [6 and H are open, thereby opening the circuit of winding II and releasing the reed unit, opening contacts 4 and 1 and 5 and 9, thereby causing the capacitor Hi to discharge and energize the primary winding [3. The vibrator movement of the reed unit is such as to swing it in the opposite direction closing contacts 4 and 6 and contacts 8 and 5. In this swinging movement, contacts i6 and I! are again closed. The closing of contacts 4 and 6 and 5 and 8 establishes an energizing current to the capacitor I2 in the opposite'direction and, at the same time, the

closing of contacts l6 and i1 re-energizes the winding I2 causing the vibrator to again swing This reed 2 is connected with in the opposite direction opening contacts I and 8 and I and O, and thus causing the capacitor I2 to discharge through the primary winding it of the transformer in the opposite direction.

The above construction contemplates that the natural vibration frequency of the vibrator element or unit comprising the reeds I and 3 is substantially equal to the frequency to which the series circuit including the winding i3 and the capacitor l2 tunes. In actual practice, I have found that although theoretically the vibration frequency of the reed element is the same as the frequency to which the series circuit tunes, more'advantageous results are obtained if the natural vibration frequency of the vibrating element is less by a predetermined amount than the frequency to which the series circuit tunes. By providing for this slight differential, the current through the switch i at the closed contact periods is reduced to zero before the contacts open and sparking at the contacts is practically eliminated.

In Fig. 2, I have illustrated a modification of the structure illustrated in Fig. 1 wherein, in order to reduce sparking at the contacts controlling the circuit through the energizing winding I I, I have introduced in the circuit of this energizing winding a resistance [9. The value of this resistance is relatively high but is sufiiciently low to pass sufficient energizing current for the coil ii.

In the structure illustrated in Fig. 3, I have shown a still further modification of the invention.

equivalent. The secondary I 3' constitutes the stationary windings of the alternating current self starting electric motor and,'in effect, the secondary comprises the rotor winding 20. I

In each of the structures illustrated, however,

In this structure, the load consists of a small alternating current electric motor or its it will be noted that I have provided what may be termed a series circuit including a capacitor which is alternately charged and discharged in opposite directions through the medium of a vibrating switch, and that I have also provided a circuit for operating the vibrating. switch which is independent of the series circuit so that at no time is there danger of failure of the vibrator to operate as would be the case if, for instance.

the capacitor were included in the circuit of the 1 energizing coil of the vibrator at some period.

I claim as my invention:

1. In an electric system for converting direct current into alternating current, said system having a transformer with input and output windings, a source of direct current supply, a series input circuit including said input winding, a capacitor and a vibratory reed switch having movable contacts on said reed cooperating with stationary contacts to alternately connect said input circuit including said input winding and capacitor with said source of direct current in opposite directions, the vibrating frequency of said reed being substantially the same as the frequency to which said series circuit is tuned to effect the opening of said series circuit substantially at the time the switch contacts-are carrying a minimum current and an actuating winding for said switch energized from a source of direct current, the circuit of said winding being intermittently opened and closed by said switch.

2. In an electric system for converting direct current into alternating current, said system having a transformer with input and output windings, a source of direct current supply, a series input circuit including said input winding,

a capacitor and a vibrating reed switch having movable contacts on said reed cooperating with stationary contacts to alternately connect said input circuit including said input winding and capacitor with saidsource of direct current in opposite directions, the vibrating frequency of said reed being substantially the same as the frequency to which said series circuit is tuned to effect the opening of said circuit substantially at the time the switch contacts are carrying a minimum current, and a circuit including an energizing winding for said switch independentof said primary and capacitor circuit and intermittently opened and closed by said switch.

3. In an electric system for converting direct current into alternating current, said system having a transformer with input and output windings, a source of direct current supply, a series input circuit including said input windings, a capacitor and a vibratory reed switch having movable contacts on said reed cooperating with stationary contacts to alternately connect said input circuit including said series input winding and capacitor with said source of direct current in opposite directions, the vibrating frequency of said reed being substantially the same as the frequency to which said series circuit is tuned td 'efiect the opening of said circuit substantially at the time the switch. contacts are carrying a minimum current and an actuating winding for said switch energized from said source and having its circuit intermittently opened and closed by said switch.

4. In an electric system for converting direct current into alternating current, said system hav ing a transformer with input and output windings, a source of direct current supply, a series input circuit including said input winding, a capacitor and a vibratory reed switch having movable contacts on said reed cooperating with stationary contacts to alternately connect said input circuit including said series input windings and said capacitor with said source of direct current in opposite directions, the vibrating frequency of said reed being substantially the same as the frequency to which said series circuit is tuned to effect the opening of said circuit substantially at the time the switch contacts are carrying a minimum current, and an independent circuit energized from said source and including a winding for said switch and alternately opened and closed by said switch.

5. In an electric system for converting direct current into alternating current, said system having a transformer with input and output windings, a source of direct current supply, a series input circuit including said input windings, a capacitor and a vibrating reed switch having movable contact on said reed cooperating with stationary contacts to alternately connect said input circuit including said input winding and capacitor with said source of direct current and reverse the polarity of the circuit through the capacitor and winding, the vibrating frequency of said reed being substantially the same as the frequency to which said series circuit is tuned to effect the opening of said circuit substantially at the time the switch contacts are carrying a minimum current, and an actuating winding for said switch energized from said source of direct current, the circuit of .said winding being intermittently opened and closed by said switch.

6. In an electric system for converting direct current into alternating current, said system having a transformer with input and output windings, a source of direct current supply, a

series input circuit including said input winding, a

a capacitor and a vibratory reed switch having movable contacts on said reed cooperating with stationary contacts to connect said input circuit with said source and reverse the polarity of the current from said source through the primary winding and capacitor, the vibrating frequency 10 of said reed being substantially the same as the frequency to which said series circuit is tuned to effect the opening of said circuit substantially at the time the switch contacts are carrying a minimum current, and a circuit independent of said primary winding including a winding'for said switch and intermittently opened and closed by said switch.

WILLIAM W. GARS'IANG. 

